-Inhibits nutrient absorption.-Excessive H2O and electrolyte loss.• Bacterial • Viral• Parasites • Poisoning by

microbial toxins .• food borne

intoxication.

It is the inflammation of the stomach or

intestine

Signs and Symptoms:

diarrhea loss of appetite

abdominal cramps

nauseapossibly feverDysentery

Escherichia coli

Escherichia coli commonly abbreviated E. coli is a gram-negative, facultative anaerobic, rod-shaped, nonsporulating.

Five virulence groups of E. coli are recognized:1. enteroaggregative(EAggEC),

2. enterohemorrhagic (EHEC),3. enteroinvasive (EIEC),4. enteropathogenic(EPEC), and5. enterotoxigenic (ETEC).

• •Have fimbriae which aggregate tissue culture cells.• EAEC bind to the intestinal mucosa to cause watery diarrhea without fever. • They are noninvasive.•An enteroaggregative E. coli (EAEC) strain of serotype O92:H33 was found to be the causative agent . The strain showed an aggregative pattern of adherence to HEp-2 cells, did not produce a biofilm .

Enteroaggregative(EAggEC)

Enterohemorrhagic (EHEC)

Enteroinvasive (EIEC)EIEC infection causes a syndrome that is identical to shigellosis, with profuse diarrhea and high fever. highly invasive, and they utilize adhesion proteins to bind to and enter intestinal cells. They produce no toxins, but severely damage the intestinal wall through mechanical cell destruction.

After the E. coil strain pass through the epithelial by penetration, the endocytosis vacuole gets lysed, the strain multiplies using the host cell machinery, extend to the adjacent epithelial cell.

The invasion of the cells can trigger a mild form of diarrhea or dysentery, often mistaken for dysentery caused by Shigella species

Like ETEC, EPEC also causes diarrhea.EPEC lack fimbriae, ST and LT toxins, but they use an adhesin known as intimin to bind host intestinal cells. This virotype has an array of virulence factors that are similar to those found in Shigella, and may possess a shiga toxin. Adherence to the intestinal mucosa causes a rearrangement of actins in the host cell, causing significant deformation. EPEC cells are moderately invasive and elicit an inflammatory response. Changes in intestinal cell ultra structure due to "attachment and effacement" is likely the prime cause of diarrhea .

Enteropathogenic E. coli (EPEC)

ETEC uses fimbrial adhesins(projections from the bacterial cell surface) to bind enterocyte cells in the small intestine ETEC can produce two proteinaceous enterotoxin: The larger of the

two proteins, LT enterotoxin, is similar to cholera toxin in structure and function.

The smaller protein, ST enterotoxin causes cGMP accumulation in the target cells and a subsequent secretion of fluid and electrolytes into the intestinal lumen.ETEC strains are noninvasive, and they do not leave the intestinal lumen. ETEC is the leading bacterial cause of diarrhea in children in the developing world, as well as the most common cause of travelers diarrhea . Each year, ETEC causes more than 200 million cases of diarrhea and 380,000 deaths, mostly in children in developing countries

Enterotoxigenic (ETEC).

.

Shiga toxin-producing Escherichia coli (STEC)THE strains have emerged as an important cause of serious human gastrointestinal disease, which may result in life-threatening complications such as hemolytic-uremic syndrome.

Acquired as a food borne or from a contaminated water supply and caused

by E.coli O157:H7

Main causative agent

Schistocyte

Prevention • Hand washing• Proper food handling and complete

cooking• Pasteurization of milk and juices • Adequate sanitation• Safe water supplies

Treatment• Rapid replacement of fluids and

electrolytes• Anti-nausea medication • Antimicrobials may be used in

severe cases.

For illness caused by E. coli O157:H7, no current treatments can cure the infection, relieve symptoms or prevent complications. For most people, the best option is to rest and drink plenty of fluids to help with dehydration and fatigue. Avoid taking an anti-diarrheal medication — this slows your digestive system down, preventing your body from getting rid of the toxins.

Cheerfulness is the best promoter of health and is as friendly to the mind as to the body. Be strong ……….